gdb/inftarg.c

   1 /* Target-vector operations for controlling Unix child processes, for GDB.
   2
   3    Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999,
   4    2000, 2002, 2003 Free Software Foundation, Inc.
   5
   6    Contributed by Cygnus Support.
   7
   8    ## Contains temporary hacks..
   9
  10    This file is part of GDB.
  11
  12    This program is free software; you can redistribute it and/or modify
  13    it under the terms of the GNU General Public License as published by
  14    the Free Software Foundation; either version 2 of the License, or
  15    (at your option) any later version.
  16
  17    This program is distributed in the hope that it will be useful,
  18    but WITHOUT ANY WARRANTY; without even the implied warranty of
  19    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20    GNU General Public License for more details.
  21
  22    You should have received a copy of the GNU General Public License
  23    along with this program; if not, write to the Free Software
  24    Foundation, Inc., 59 Temple Place - Suite 330,
  25    Boston, MA 02111-1307, USA.  */
  26
  27 #include "defs.h"
  28 #include "frame.h"              /* required by inferior.h */
  29 #include "inferior.h"
  30 #include "target.h"
  31 #include "gdbcore.h"
  32 #include "command.h"
  33 #include "gdb_stat.h"
  34 #include <signal.h>
  35 #include <sys/types.h>
  36 #include <fcntl.h>
  37
  38 #include "gdb_wait.h"
  39 #include "inflow.h"
  40
  41 extern struct symtab_and_line *child_enable_exception_callback (enum
  42                                                                 exception_event_kind,
  43                                                                 int);
  44
  45 extern struct exception_event_record
  46   *child_get_current_exception_event (void);
  47
  48 extern void _initialize_inftarg (void);
  49
  50 static void child_prepare_to_store (void);
  51
  52 #ifndef CHILD_WAIT
  53 static ptid_t child_wait (ptid_t, struct target_waitstatus *);
  54 #endif /* CHILD_WAIT */
  55
  56 #if !defined(CHILD_POST_WAIT)
  57 void child_post_wait (ptid_t, int);
  58 #endif
  59
  60 static void child_open (char *, int);
  61
  62 static void child_files_info (struct target_ops *);
  63
  64 static void child_detach (char *, int);
  65
  66 static void child_attach (char *, int);
  67
  68 #if !defined(CHILD_POST_ATTACH)
  69 extern void child_post_attach (int);
  70 #endif
  71
  72 static void ptrace_me (void);
  73
  74 static void ptrace_him (int);
  75
  76 static void child_create_inferior (char *, char *, char **);
  77
  78 static void child_mourn_inferior (void);
  79
  80 static int child_can_run (void);
  81
  82 static void child_stop (void);
  83
  84 #ifndef CHILD_THREAD_ALIVE
  85 int child_thread_alive (ptid_t);
  86 #endif
  87
  88 static void init_child_ops (void);
  89
  90 extern char **environ;
  91
  92 struct target_ops child_ops;
  93
  94 int child_suppress_run = 0;     /* Non-zero if inftarg should pretend not to
  95                                    be a runnable target.  Used by targets
  96                                    that can sit atop inftarg, such as HPUX
  97                                    thread support.  */
  98
  99 #ifndef CHILD_WAIT
 100
 101 /* Wait for child to do something.  Return pid of child, or -1 in case
 102    of error; store status through argument pointer OURSTATUS.  */
 103
 104 static ptid_t
 105 child_wait (ptid_t ptid, struct target_waitstatus *ourstatus)
 106 {
 107   int save_errno;
 108   int status;
 109   char *execd_pathname = NULL;
 110   int exit_status;
 111   int related_pid;
 112   int syscall_id;
 113   enum target_waitkind kind;
 114   int pid;
 115
 116   do
 117     {
 118       set_sigint_trap ();       /* Causes SIGINT to be passed on to the
 119                                    attached process. */
 120       set_sigio_trap ();
 121
 122       pid = ptrace_wait (inferior_ptid, &status);
 123
 124       save_errno = errno;
 125
 126       clear_sigio_trap ();
 127
 128       clear_sigint_trap ();
 129
 130       if (pid == -1)
 131         {
 132           if (save_errno == EINTR)
 133             continue;
 134
 135           fprintf_unfiltered (gdb_stderr, "Child process unexpectedly missing: %s.\n",
 136                               safe_strerror (save_errno));
 137
 138           /* Claim it exited with unknown signal.  */
 139           ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
 140           ourstatus->value.sig = TARGET_SIGNAL_UNKNOWN;
 141           return pid_to_ptid (-1);
 142         }
 143
 144       /* Did it exit?
 145        */
 146       if (target_has_exited (pid, status, &exit_status))
 147         {
 148           /* ??rehrauer: For now, ignore this. */
 149           continue;
 150         }
 151
 152       if (!target_thread_alive (pid_to_ptid (pid)))
 153         {
 154           ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
 155           return pid_to_ptid (pid);
 156         }
 157       } while (pid != PIDGET (inferior_ptid)); /* Some other child died or stopped */
 158
 159   store_waitstatus (ourstatus, status);
 160   return pid_to_ptid (pid);
 161 }
 162 #endif /* CHILD_WAIT */
 163
 164 #if !defined(CHILD_POST_WAIT)
 165 void
 166 child_post_wait (ptid_t ptid, int wait_status)
 167 {
 168   /* This version of Unix doesn't require a meaningful "post wait"
 169      operation.
 170    */
 171 }
 172 #endif
 173
 174
 175 #ifndef CHILD_THREAD_ALIVE
 176
 177 /* Check to see if the given thread is alive.
 178
 179    FIXME: Is kill() ever the right way to do this?  I doubt it, but
 180    for now we're going to try and be compatable with the old thread
 181    code.  */
 182 int
 183 child_thread_alive (ptid_t ptid)
 184 {
 185   pid_t pid = PIDGET (ptid);
 186
 187   return (kill (pid, 0) != -1);
 188 }
 189
 190 #endif
 191
 192 /* Attach to process PID, then initialize for debugging it.  */
 193
 194 static void
 195 child_attach (char *args, int from_tty)
 196 {
 197   if (!args)
 198     error_no_arg ("process-id to attach");
 199
 200 #ifndef ATTACH_DETACH
 201   error ("Can't attach to a process on this machine.");
 202 #else
 203   {
 204     char *exec_file;
 205     int pid;
 206     char *dummy;
 207
 208     dummy = args;
 209     pid = strtol (args, &dummy, 0);
 210     /* Some targets don't set errno on errors, grrr! */
 211     if ((pid == 0) && (args == dummy))
 212       error ("Illegal process-id: %s\n", args);
 213
 214     if (pid == getpid ())       /* Trying to masturbate? */
 215       error ("I refuse to debug myself!");
 216
 217     if (from_tty)
 218       {
 219         exec_file = (char *) get_exec_file (0);
 220
 221         if (exec_file)
 222           printf_unfiltered ("Attaching to program: %s, %s\n", exec_file,
 223                              target_pid_to_str (pid_to_ptid (pid)));
 224         else
 225           printf_unfiltered ("Attaching to %s\n",
 226                              target_pid_to_str (pid_to_ptid (pid)));
 227
 228         gdb_flush (gdb_stdout);
 229       }
 230
 231     attach (pid);
 232
 233     inferior_ptid = pid_to_ptid (pid);
 234     push_target (&child_ops);
 235   }
 236 #endif /* ATTACH_DETACH */
 237 }
 238
 239 #if !defined(CHILD_POST_ATTACH)
 240 void
 241 child_post_attach (int pid)
 242 {
 243   /* This version of Unix doesn't require a meaningful "post attach"
 244      operation by a debugger.  */
 245 }
 246 #endif
 247
 248 /* Take a program previously attached to and detaches it.
 249    The program resumes execution and will no longer stop
 250    on signals, etc.  We'd better not have left any breakpoints
 251    in the program or it'll die when it hits one.  For this
 252    to work, it may be necessary for the process to have been
 253    previously attached.  It *might* work if the program was
 254    started via the normal ptrace (PTRACE_TRACEME).  */
 255
 256 static void
 257 child_detach (char *args, int from_tty)
 258 {
 259 #ifdef ATTACH_DETACH
 260   {
 261     int siggnal = 0;
 262     int pid = PIDGET (inferior_ptid);
 263
 264     if (from_tty)
 265       {
 266         char *exec_file = get_exec_file (0);
 267         if (exec_file == 0)
 268           exec_file = "";
 269         printf_unfiltered ("Detaching from program: %s, %s\n", exec_file,
 270                            target_pid_to_str (pid_to_ptid (pid)));
 271         gdb_flush (gdb_stdout);
 272       }
 273     if (args)
 274       siggnal = atoi (args);
 275
 276     detach (siggnal);
 277
 278     inferior_ptid = null_ptid;
 279     unpush_target (&child_ops);
 280   }
 281 #else
 282   error ("This version of Unix does not support detaching a process.");
 283 #endif
 284 }
 285
 286 /* Get ready to modify the registers array.  On machines which store
 287    individual registers, this doesn't need to do anything.  On machines
 288    which store all the registers in one fell swoop, this makes sure
 289    that registers contains all the registers from the program being
 290    debugged.  */
 291
 292 static void
 293 child_prepare_to_store (void)
 294 {
 295 #ifdef CHILD_PREPARE_TO_STORE
 296   CHILD_PREPARE_TO_STORE ();
 297 #endif
 298 }
 299
 300 /* Print status information about what we're accessing.  */
 301
 302 static void
 303 child_files_info (struct target_ops *ignore)
 304 {
 305   printf_unfiltered ("\tUsing the running image of %s %s.\n",
 306       attach_flag ? "attached" : "child", target_pid_to_str (inferior_ptid));
 307 }
 308
 309 static void
 310 child_open (char *arg, int from_tty)
 311 {
 312   error ("Use the \"run\" command to start a Unix child process.");
 313 }
 314
 315 /* Stub function which causes the inferior that runs it, to be ptrace-able
 316    by its parent process.  */
 317
 318 static void
 319 ptrace_me (void)
 320 {
 321   /* "Trace me, Dr. Memory!" */
 322   call_ptrace (0, 0, (PTRACE_ARG3_TYPE) 0, 0);
 323 }
 324
 325 /* Stub function which causes the GDB that runs it, to start ptrace-ing
 326    the child process.  */
 327
 328 static void
 329 ptrace_him (int pid)
 330 {
 331   push_target (&child_ops);
 332
 333   /* On some targets, there must be some explicit synchronization
 334      between the parent and child processes after the debugger
 335      forks, and before the child execs the debuggee program.  This
 336      call basically gives permission for the child to exec.
 337    */
 338
 339   target_acknowledge_created_inferior (pid);
 340
 341   /* START_INFERIOR_TRAPS_EXPECTED is defined in inferior.h,
 342    * and will be 1 or 2 depending on whether we're starting
 343    * without or with a shell.
 344    */
 345   startup_inferior (START_INFERIOR_TRAPS_EXPECTED);
 346
 347   /* On some targets, there must be some explicit actions taken after
 348      the inferior has been started up.
 349    */
 350   target_post_startup_inferior (pid_to_ptid (pid));
 351 }
 352
 353 /* Start an inferior Unix child process and sets inferior_ptid to its pid.
 354    EXEC_FILE is the file to run.
 355    ALLARGS is a string containing the arguments to the program.
 356    ENV is the environment vector to pass.  Errors reported with error().  */
 357
 358 static void
 359 child_create_inferior (char *exec_file, char *allargs, char **env)
 360 {
 361 #ifdef HPUXHPPA
 362   fork_inferior (exec_file, allargs, env, ptrace_me, ptrace_him, pre_fork_inferior, NULL);
 363 #else
 364   fork_inferior (exec_file, allargs, env, ptrace_me, ptrace_him, NULL, NULL);
 365 #endif
 366   /* We are at the first instruction we care about.  */
 367   /* Pedal to the metal... */
 368   proceed ((CORE_ADDR) -1, TARGET_SIGNAL_0, 0);
 369 }
 370
 371 #if !defined(CHILD_POST_STARTUP_INFERIOR)
 372 void
 373 child_post_startup_inferior (ptid_t ptid)
 374 {
 375   /* This version of Unix doesn't require a meaningful "post startup inferior"
 376      operation by a debugger.
 377    */
 378 }
 379 #endif
 380
 381 #if !defined(CHILD_ACKNOWLEDGE_CREATED_INFERIOR)
 382 void
 383 child_acknowledge_created_inferior (int pid)
 384 {
 385   /* This version of Unix doesn't require a meaningful "acknowledge created inferior"
 386      operation by a debugger.
 387    */
 388 }
 389 #endif
 390
 391
 392 #if !defined(CHILD_INSERT_FORK_CATCHPOINT)
 393 int
 394 child_insert_fork_catchpoint (int pid)
 395 {
 396   /* This version of Unix doesn't support notification of fork events.  */
 397   return 0;
 398 }
 399 #endif
 400
 401 #if !defined(CHILD_REMOVE_FORK_CATCHPOINT)
 402 int
 403 child_remove_fork_catchpoint (int pid)
 404 {
 405   /* This version of Unix doesn't support notification of fork events.  */
 406   return 0;
 407 }
 408 #endif
 409
 410 #if !defined(CHILD_INSERT_VFORK_CATCHPOINT)
 411 int
 412 child_insert_vfork_catchpoint (int pid)
 413 {
 414   /* This version of Unix doesn't support notification of vfork events.  */
 415   return 0;
 416 }
 417 #endif
 418
 419 #if !defined(CHILD_REMOVE_VFORK_CATCHPOINT)
 420 int
 421 child_remove_vfork_catchpoint (int pid)
 422 {
 423   /* This version of Unix doesn't support notification of vfork events.  */
 424   return 0;
 425 }
 426 #endif
 427
 428 #if !defined(CHILD_FOLLOW_FORK)
 429 int
 430 child_follow_fork (int follow_child)
 431 {
 432   /* This version of Unix doesn't support following fork or vfork events.  */
 433   return 0;
 434 }
 435 #endif
 436
 437 #if !defined(CHILD_INSERT_EXEC_CATCHPOINT)
 438 int
 439 child_insert_exec_catchpoint (int pid)
 440 {
 441   /* This version of Unix doesn't support notification of exec events.  */
 442   return 0;
 443 }
 444 #endif
 445
 446 #if !defined(CHILD_REMOVE_EXEC_CATCHPOINT)
 447 int
 448 child_remove_exec_catchpoint (int pid)
 449 {
 450   /* This version of Unix doesn't support notification of exec events.  */
 451   return 0;
 452 }
 453 #endif
 454
 455 #if !defined(CHILD_REPORTED_EXEC_EVENTS_PER_EXEC_CALL)
 456 int
 457 child_reported_exec_events_per_exec_call (void)
 458 {
 459   /* This version of Unix doesn't support notification of exec events.
 460    */
 461   return 1;
 462 }
 463 #endif
 464
 465 #if !defined(CHILD_HAS_EXITED)
 466 int
 467 child_has_exited (int pid, int wait_status, int *exit_status)
 468 {
 469   if (WIFEXITED (wait_status))
 470     {
 471       *exit_status = WEXITSTATUS (wait_status);
 472       return 1;
 473     }
 474
 475   if (WIFSIGNALED (wait_status))
 476     {
 477       *exit_status = 0;         /* ?? Don't know what else to say here. */
 478       return 1;
 479     }
 480
 481   /* ?? Do we really need to consult the event state, too?  Assume the
 482      wait_state alone suffices.
 483    */
 484   return 0;
 485 }
 486 #endif
 487
 488
 489 static void
 490 child_mourn_inferior (void)
 491 {
 492   unpush_target (&child_ops);
 493   generic_mourn_inferior ();
 494 }
 495
 496 static int
 497 child_can_run (void)
 498 {
 499   /* This variable is controlled by modules that sit atop inftarg that may layer
 500      their own process structure atop that provided here.  hpux-thread.c does
 501      this because of the Hpux user-mode level thread model.  */
 502
 503   return !child_suppress_run;
 504 }
 505
 506 /* Send a SIGINT to the process group.  This acts just like the user typed a
 507    ^C on the controlling terminal.
 508
 509    XXX - This may not be correct for all systems.  Some may want to use
 510    killpg() instead of kill (-pgrp). */
 511
 512 static void
 513 child_stop (void)
 514 {
 515   kill (-inferior_process_group, SIGINT);
 516 }
 517
 518 #if !defined(CHILD_ENABLE_EXCEPTION_CALLBACK)
 519 struct symtab_and_line *
 520 child_enable_exception_callback (enum exception_event_kind kind, int enable)
 521 {
 522   return (struct symtab_and_line *) NULL;
 523 }
 524 #endif
 525
 526 #if !defined(CHILD_GET_CURRENT_EXCEPTION_EVENT)
 527 struct exception_event_record *
 528 child_get_current_exception_event (void)
 529 {
 530   return (struct exception_event_record *) NULL;
 531 }
 532 #endif
 533
 534
 535 #if !defined(CHILD_PID_TO_EXEC_FILE)
 536 char *
 537 child_pid_to_exec_file (int pid)
 538 {
 539   /* This version of Unix doesn't support translation of a process ID
 540      to the filename of the executable file.
 541    */
 542   return NULL;
 543 }
 544 #endif
 545
 546 char *
 547 child_core_file_to_sym_file (char *core)
 548 {
 549   /* The target stratum for a running executable need not support
 550      this operation.
 551    */
 552   return NULL;
 553 }
 554
 555 /* Perform a partial transfer to/from the specified object.  For
 556    memory transfers, fall back to the old memory xfer functions.  */
 557
 558 static LONGEST
 559 child_xfer_partial (struct target_ops *ops, enum target_object object,
 560                     const char *annex, void *readbuf,
 561                     const void *writebuf, ULONGEST offset, LONGEST len)
 562 {
 563   switch (object)
 564     {
 565     case TARGET_OBJECT_MEMORY:
 566       if (readbuf)
 567         return child_xfer_memory (offset, readbuf, len, 0/*write*/,
 568                                   NULL, ops);
 569       if (writebuf)
 570         return child_xfer_memory (offset, readbuf, len, 1/*write*/,
 571                                   NULL, ops);
 572       return -1;
 573
 574     case TARGET_OBJECT_UNWIND_TABLE:
 575 #ifndef NATIVE_XFER_UNWIND_TABLE
 576 #define NATIVE_XFER_UNWIND_TABLE(OPS,OBJECT,ANNEX,WRITEBUF,READBUF,OFFSET,LEN) (-1)
 577 #endif
 578       return NATIVE_XFER_UNWIND_TABLE (ops, object, annex, readbuf, writebuf,
 579                                        offset, len);
 580
 581 #if 0
 582     case TARGET_OBJECT_AUXV:
 583       return native_xfer_auxv (PIDGET (inferior_ptid), readbuf, writebuf,
 584                                offset, len);
 585 #endif
 586
 587     default:
 588       return -1;
 589     }
 590 }
 591
 592 #if !defined(CHILD_PID_TO_STR)
 593 char *
 594 child_pid_to_str (ptid_t ptid)
 595 {
 596   return normal_pid_to_str (ptid);
 597 }
 598 #endif
 599
 600 static void
 601 init_child_ops (void)
 602 {
 603   child_ops.to_shortname = "child";
 604   child_ops.to_longname = "Unix child process";
 605   child_ops.to_doc = "Unix child process (started by the \"run\" command).";
 606   child_ops.to_open = child_open;
 607   child_ops.to_attach = child_attach;
 608   child_ops.to_post_attach = child_post_attach;
 609   child_ops.to_detach = child_detach;
 610   child_ops.to_resume = child_resume;
 611   child_ops.to_wait = child_wait;
 612   child_ops.to_post_wait = child_post_wait;
 613   child_ops.to_fetch_registers = fetch_inferior_registers;
 614   child_ops.to_store_registers = store_inferior_registers;
 615   child_ops.to_prepare_to_store = child_prepare_to_store;
 616   child_ops.to_xfer_memory = child_xfer_memory;
 617   child_ops.to_xfer_partial = child_xfer_partial;
 618   child_ops.to_files_info = child_files_info;
 619   child_ops.to_insert_breakpoint = memory_insert_breakpoint;
 620   child_ops.to_remove_breakpoint = memory_remove_breakpoint;
 621   child_ops.to_terminal_init = terminal_init_inferior;
 622   child_ops.to_terminal_inferior = terminal_inferior;
 623   child_ops.to_terminal_ours_for_output = terminal_ours_for_output;
 624   child_ops.to_terminal_save_ours = terminal_save_ours;
 625   child_ops.to_terminal_ours = terminal_ours;
 626   child_ops.to_terminal_info = child_terminal_info;
 627   child_ops.to_kill = kill_inferior;
 628   child_ops.to_create_inferior = child_create_inferior;
 629   child_ops.to_post_startup_inferior = child_post_startup_inferior;
 630   child_ops.to_acknowledge_created_inferior = child_acknowledge_created_inferior;
 631   child_ops.to_insert_fork_catchpoint = child_insert_fork_catchpoint;
 632   child_ops.to_remove_fork_catchpoint = child_remove_fork_catchpoint;
 633   child_ops.to_insert_vfork_catchpoint = child_insert_vfork_catchpoint;
 634   child_ops.to_remove_vfork_catchpoint = child_remove_vfork_catchpoint;
 635   child_ops.to_follow_fork = child_follow_fork;
 636   child_ops.to_insert_exec_catchpoint = child_insert_exec_catchpoint;
 637   child_ops.to_remove_exec_catchpoint = child_remove_exec_catchpoint;
 638   child_ops.to_reported_exec_events_per_exec_call = child_reported_exec_events_per_exec_call;
 639   child_ops.to_has_exited = child_has_exited;
 640   child_ops.to_mourn_inferior = child_mourn_inferior;
 641   child_ops.to_can_run = child_can_run;
 642   child_ops.to_thread_alive = child_thread_alive;
 643   child_ops.to_pid_to_str = child_pid_to_str;
 644   child_ops.to_stop = child_stop;
 645   child_ops.to_enable_exception_callback = child_enable_exception_callback;
 646   child_ops.to_get_current_exception_event = child_get_current_exception_event;
 647   child_ops.to_pid_to_exec_file = child_pid_to_exec_file;
 648   child_ops.to_stratum = process_stratum;
 649   child_ops.to_has_all_memory = 1;
 650   child_ops.to_has_memory = 1;
 651   child_ops.to_has_stack = 1;
 652   child_ops.to_has_registers = 1;
 653   child_ops.to_has_execution = 1;
 654   child_ops.to_magic = OPS_MAGIC;
 655 }
 656
 657 /* Take over the 'find_mapped_memory' vector from inftarg.c. */
 658 extern void
 659 inftarg_set_find_memory_regions (int (*func) (int (*) (CORE_ADDR,
 660                                                        unsigned long,
 661                                                        int, int, int,
 662                                                        void *),
 663                                               void *))
 664 {
 665   child_ops.to_find_memory_regions = func;
 666 }
 667
 668 /* Take over the 'make_corefile_notes' vector from inftarg.c. */
 669 extern void
 670 inftarg_set_make_corefile_notes (char * (*func) (bfd *, int *))
 671 {
 672   child_ops.to_make_corefile_notes = func;
 673 }
 674
 675 void
 676 _initialize_inftarg (void)
 677 {
 678 #ifdef HAVE_OPTIONAL_PROC_FS
 679   char procname[32];
 680   int fd;
 681
 682   /* If we have an optional /proc filesystem (e.g. under OSF/1),
 683      don't add ptrace support if we can access the running GDB via /proc.  */
 684 #ifndef PROC_NAME_FMT
 685 #define PROC_NAME_FMT "/proc/%05d"
 686 #endif
 687   sprintf (procname, PROC_NAME_FMT, getpid ());
 688   fd = open (procname, O_RDONLY);
 689   if (fd >= 0)
 690     {
 691       close (fd);
 692       return;
 693     }
 694 #endif
 695
 696   init_child_ops ();
 697   add_target (&child_ops);
 698 }